The persecution, sterilisation and murder of hundreds of thousands of disabled people is one of the most overlooked chapters in the whole ghastly history of Nazi Germany.

Between 1939 and 1941 as many as 100,000 people with a wide range of disabilities were dismissed as lebensunwertes Leben (‘lives unworthy of life’) and systematically killed in six converted psychiatric hospitals across Austria and Germany. Initially, lethal injections were used but soon, at Hitler’s personal recommendation, carbon monoxide was employed.

Aktion T4, as the programme was called after the war, was a logical extension of the eugenics movement, which had attracted support from a wide range of people, many with impeccable liberal credentials, across Europe and the United States. Few had suggested murder (although Virginia Woolf, confronted by a group of ‘imbeciles’, wrote in 1915 that ‘they should certainly be killed’), but the Nazi programme of compulsory sterilisation of people with ‘congenital conditions’ was widely accepted.

With the outbreak of war, the persecution escalated dramatically and, on September 1st, 1939 (the day of the invasion of Poland), Hitler signed his notorious Euthanasia Decree which stated that, ‘after a discerning diagnosis’, ‘incurable patients’ should be ‘granted mercy death’. Intellectually justified by Social Darwinism, this policy received popular support on the grounds of cost, with a poster claiming that a man ‘suffering from a hereditary defect cost “the People’s Community” 60,000 Reichmarks during his lifetime’. As a leading Nazi doctor said, ‘the idea is unbearable to me that the best, the flower of our youth, must lose its life at the front in order that feebleminded and irresponsible asocial elements can have a secure existence in the asylum.’

By 1941, 5000 children, many only a few months old, with a wide range of conditions—Down syndrome, ‘idiocy’, cerebral palsy, and so on—had been assessed, registered and murdered. Initially, their parents were asked for their consent and a panel of three ‘medical experts’ was convened to agree on the course of action. In due course, however, deception and social pressure were deployed, and children were sent to so-called ‘special sections’, apparently to receive medical treatment, but instead bussed off to their deaths.

Public opposition to the programme was limited. Probably the most striking intervention came from the churches, especially the Catholic Bishop of Münster. Clemens August Graf von Galen (1878-1946) belonged to one of the oldest aristocratic families in Germany. He spent 23 years (1906-29) working as a parish priest in a poor district in Berlin but, as a staunch conservative, had opposed what he perceived to be the immorality of the Weimar Republic. Indeed, the Nazis, who saw him as an ally, welcomed his installation as Bishop of Münster in 1933. From the outset, however, he objected to many aspects of the regime, and took editorial responsibility for a volume of essays criticising the paganism of the philosopher and ideologue Alfred Rosenberg. He voiced his disapproval of Nazi racial theories and helped draft Pope Pius XI’s anti-Nazi encyclical Mit brennender Sorge (1937).

He is best known, however, for his criticism of the murder of the disabled and, in July and August 1941, delivered three sermons which didn’t just criticise the programme they challenged the entire Nazi value system. In one of them he asked why these ‘unproductive citizens’ were killed:

'The opinion is that since they can no longer make money, they are obsolete machines, comparable with some old cow that can no longer give milk or some horse that has gone lame. What is the lot of unproductive machines and cattle? They are destroyed. I have no intention of stretching this comparison further. The case here is not one of machines or cattle which exist to serve men and furnish them with plenty. They may be legitimately done away with when they can no longer fulfill their function. Here we are dealing with human beings, with our neighbours, brothers and sisters, the poor and invalids ... unproductive—perhaps! But have they, therefore, lost the right to live? Have you or I the right to exist only because we are ‘productive’? If the principle is established that unproductive human beings may be killed, then God help all those invalids who, in order to produce wealth, have given their all and sacrificed their strength of body. If all unproductive people may thus be violently eliminated, then woe betide our bravesoldiers who return home, wounded, maimed or sick.'

Thousands of copies of the sermons were illegally circulated and local protest groups broke the silence that surrounded the programme. Copies were also dropped by the RAF and inspired various resistance groups.

The Nazis were in two minds about how to respond to the ‘Lion of Münster’. Some advised Hitler to execute von Galen or, at least, send him to a concentration camp; but others, especially Goebbels and Bormann, recognised the danger of alienating German Catholics at such a crucial time in the war, and von Galen—a close friend of the new Pope, Pius XII—was subjected to house arrest from late 1941 onwards. Hitler declared ominously in a private conversation that ‘the fact that I remain silent in public over Church affairs is not in the least misunderstood by the sly foxes of the Catholic Church, and I am quite sure that a man like Bishop von Galen knows full well that after the war I shall extract retribution to the last farthing’. But von Galen survived Hitler, dying of natural causes in 1946, and was beatified by his fellow German, Benedict XVI, in 2005.

Astonishingly, partly as a result of von Galen’s intervention, the programmewas formally discontinued in August 1941. It would be overstating the case to say that he stopped the murder (a further 100,000 disabled people were killed before the end of the war), and many of the techniques and personnel were employed in the far greater Jewish Holocaust that escalated so dramatically after 1941. Nevertheless, his denunciation was one of the most courageous and outspoken acts of resistance in Third Reich.

All Our Children is very much a work of fiction. There is no evidence that von Galen had a meeting of the kind that I have dramatised (though he did talk with senior figures in the SS) nor do we know of a doctor involved in the programme having qualms about what he was doing. What’s clear, however, is that his intervention raised the most profound questions about the innate value of the human being, regardless of cost or productivity, and his voice, for all its stubborn absolutism, deserves to be heard.

It would be absurd to claim that disabled children face anything like this level of discrimination today. Nevertheless, there is a huge amount to be done to ensure that they’re given the same opportunities as their able-bodied siblings. It’s often said that you can judge a society by the way that it treats its most vulnerable. If Nazi Germany failed that test in the most abject way imaginable, we should never forget its terrible lessons.